added histograms calculation to gpu module

modules/gpu/include/opencv2/gpu/gpu.hpp

@@ -700,6 +700,31 @@ namespace cv
         //!performs labeling via graph cuts
         CV_EXPORTS void graphcut(GpuMat& terminals, GpuMat& leftTransp, GpuMat& rightTransp, GpuMat& top, GpuMat& bottom, GpuMat& labels, GpuMat& buf);
 
+        ////////////////////////////////// Histograms //////////////////////////////////
+
+        //! Compute levels with even distribution. levels will have 1 row and nLevels cols and CV_32SC1 type.
+        CV_EXPORTS void evenLevels(GpuMat& levels, int nLevels, int lowerLevel, int upperLevel);
+        //! Calculates histogram with evenly distributed bins for signle channel source.
+        //! Supports CV_8UC1, CV_16UC1 and CV_16SC1 source types.
+        //! Output hist will have one row and histSize cols and CV_32SC1 type.
+        CV_EXPORTS void histEven(const GpuMat& src, GpuMat& hist, int histSize, int lowerLevel, int upperLevel);
+        //! Calculates histogram with evenly distributed bins for four-channel source.
+        //! All channels of source are processed separately.
+        //! Supports CV_8UC4, CV_16UC4 and CV_16SC4 source types.
+        //! Output hist[i] will have one row and histSize[i] cols and CV_32SC1 type.
+        CV_EXPORTS void histEven(const GpuMat& src, GpuMat hist[4], int histSize[4], int lowerLevel[4], int upperLevel[4]);
+        //! Calculates histogram with bins determined by levels array.
+        //! levels must have one row and CV_32SC1 type.
+        //! Supports CV_8UC1, CV_16UC1 and CV_16SC1 source types.
+        //! Output hist will have one row and (levels.cols-1) cols and CV_32SC1 type.
+        CV_EXPORTS void histRange(const GpuMat& src, GpuMat& hist, const GpuMat& levels);
+        //! Calculates histogram with bins determined by levels array.
+        //! All levels must have one row and CV_32SC1 type.
+        //! All channels of source are processed separately.
+        //! Supports CV_8UC4, CV_16UC4 and CV_16SC4 source types.
+        //! Output hist[i] will have one row and (levels[i].cols-1) cols and CV_32SC1 type.
+        CV_EXPORTS void histRange(const GpuMat& src, GpuMat hist[4], const GpuMat levels[4]);
+
         //////////////////////////////// StereoBM_GPU ////////////////////////////////
 
         class CV_EXPORTS StereoBM_GPU

tests/gpu/src/imgproc_gpu.cpp

@@ -530,6 +530,80 @@ void CV_GpuCvtColorTest::run( int )
     ts->set_failed_test_info(testResult);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// Histograms
+class CV_GpuHistogramsTest : public CvTest
+{
+public:
+    CV_GpuHistogramsTest() : CvTest("GPU-Histograms", "histEven") {}
+    ~CV_GpuHistogramsTest() {};
+
+protected:
+    void run(int);
+
+    int CheckNorm(const Mat& m1, const Mat& m2)
+    {
+        double ret = norm(m1, m2, NORM_INF);
+
+        if (ret < std::numeric_limits<double>::epsilon())
+        {
+            return CvTS::OK;
+        }
+        else
+        {
+            ts->printf(CvTS::LOG, "\nNorm: %f\n", ret);
+            return CvTS::FAIL_GENERIC;
+        }
+    }
+};
+
+void CV_GpuHistogramsTest::run( int )
+{
+    //load image
+    cv::Mat img = cv::imread(std::string(ts->get_data_path()) + "stereobp/aloe-L.png");
+
+    if (img.empty())
+    {
+        ts->set_failed_test_info(CvTS::FAIL_MISSING_TEST_DATA);
+        return;
+    }
+
+    try
+    {
+        Mat hsv;
+        cv::cvtColor(img, hsv, CV_BGR2HSV);
+
+        int hbins = 30;
+        int histSize[] = {hbins};
+
+        float hranges[] = {0, 180};
+        const float* ranges[] = {hranges};
+
+        MatND hist;
+        
+        int channels[] = {0};
+        calcHist(&hsv, 1, channels, Mat(), hist, 1, histSize, ranges);
+
+        GpuMat gpuHsv(hsv);
+        std::vector<GpuMat> srcs;
+        cv::gpu::split(gpuHsv, srcs);
+        GpuMat gpuHist;
+        histEven(srcs[0], gpuHist, hbins, (int)hranges[0], (int)hranges[1]);
+
+        Mat cpuHist = hist;
+        cpuHist = cpuHist.t();
+        cpuHist.convertTo(cpuHist, CV_32S);
+
+        ts->set_failed_test_info(CheckNorm(cpuHist, gpuHist));
+    }
+    catch(const cv::Exception& e)
+    {
+        if (!check_and_treat_gpu_exception(e, ts))
+            throw;
+        return;
+    }
+}
+
 /////////////////////////////////////////////////////////////////////////////
 /////////////////// tests registration  /////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////
@@ -545,4 +619,5 @@ CV_GpuNppImageWarpAffineTest CV_GpuNppImageWarpAffine_test;
 CV_GpuNppImageWarpPerspectiveTest CV_GpuNppImageWarpPerspective_test;
 CV_GpuNppImageIntegralTest CV_GpuNppImageIntegral_test;
 CV_GpuNppImageCannyTest CV_GpuNppImageCanny_test;
-CV_GpuCvtColorTest CV_GpuCvtColor_test;
\ No newline at end of file
+CV_GpuCvtColorTest CV_GpuCvtColor_test;
+CV_GpuHistogramsTest CV_GpuHistograms_test;
\ No newline at end of file